Preoperative Planning of a Pedicled Anterolateral Thigh (ALT) Flap for Penile Reconstruction with the Multidetector CT Scan

Abstract

Introduction:

Recently, perforator flap surgery has been introduced in phalloplasty procedures. Especially the anterolateral thigh (ALT) flap has found its application as a pedicled flap for the penile reconstruction. Adequate shaping of the flap and the need of transferring the shaped flap on its pedicle to the pubic area requires precise localisation and preoperative evaluation of the perforators. Also preoperative measurement of the subcutaneous fat tissue is necessary to allow adequate patient selection and optimal shaping of the phallus. The objective of this report is to demonstrate the usefulness of a multidetector CT scan (MDCT) in the preoperative planning of patients undergoing an ALT flap phalloplasty.

Methods:

Between September 2009 and July 2011, 13 patients were operated for ALT phalloplasty and had preoperative perforator mapping with the MDCT. An algorithm was set up to select the best perforator. Indocyanine green angiography was used in 5 patients to confirm the perforator selection. A mathematical formula was developed to calculate the necessary flap width from the flap thickness.

Results:

Accurate identification of the main perforators was achieved in all patients with a very satisfactory concordance between the MDCT scan and surgical findings. Indocyanine green angiography confirmed the MDCT perforator selection in all cases. The flap size could be determined preoperatively in all patients by measuring the thickness of the subcutaneous fat layer.

Conclusions:

Preoperative evaluation of ALT perforators and the subcutaneous fat tissue layer is feasible with an MDCT scan and provides precise data to make an adequate patient and perforator selection and determine the exact flap size.

Zusammenfassung

Einleitung

In jüngerer Zeit werden Perforans-Lappenplastiken für die Phalloplastik zunehmend eingesetzt. Vor allem der anterolaterale Oberschenkel-Lappenplastik (ALT Flap) wird als gestielter Lappen oftmals für die penile Rekonstruktion verwendet. Die adäquate Formung des Lappens und die Notwendigkeit der Verlagerung des geformten Lappens an seinem Stiel in die pubische Region erfordert die präzise Lokalisation und präoperative Evaluation der Perforatoren. Zudem ist präoperativ die Messung des subkutanen Fettgewebes notwendig, um eine adäquate Patientenauswahl und eine optimale Formung des Phallus zu ermöglichen. Ziel dieser Untersuchung ist die Nutzendarstellung von Multidetektor CT Scans (MDCT) für die präopera­tive Planung bei ALT-Lappenplastik Phalloplastik.

Methoden:

Zwischen September 2009 und Juli 2011 erhielten 13 Patienten eine ALT Phalloplastik und ein präoperatives Perforator-Mapping mittels MDCT. Ein Algorithmus zur Auswahl des besten Perforators wurde etabliert. 5 Patienten erhielten zusätzlich eine Indocyaningrün Angio­grafie zur Bestätigung der Perforator Auswahl. Zur Berechnung der erforderlichen Lappenbreite aus der Lappendicke wurde eine mathematische Formel entwickelt.

Ergebnisse:

Eine akkurate Identifizierung des dominanten Perforators wurde bei allen Patienten erreicht, die Übereinstimmung zwischen der MDCT und den intraoperativen Ergebnissen war sehr gut. Die Indocyaningrün Angiografie bestätigte die MDCT Perforator Auswahl in allen Fällen. Die Lappengröße konnte präoperativ bei allen Patienten anhand der Dickenmessung des subkutanen Fettgewebes bestimmt werden.

Schlussfolgerungen:

MDCT ermöglicht die präoperative Bewertung der ALT Perforatoren und des subkutanen Fettgewebes und hiermit eine adäquate Patienten und Perforator Auswahl wie auch die Bestimmung der exakten Lappengröße.

Key words

interdisciplinary plastic surgery - transsexualism - urological plastic surgery - genital organs - pedicled flap - perforator flap

Schlüsselwörter

interdisziplinäre plastische Chirurgie - Transsexualität - urologische plastische Chirurgie - Genitalorgane - gestielter Lappen - Perforator-Lappen

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